Robust optimisation of source power and relay beamforming in multiuser wireless networks

In this work, a novel design for a highly non-convex problem of joint optimisation of source power and relay beamforming vector in multi-user systems is presented. Taking into account imperfect channel-state information, the design problem is formulated as a non-convex optimisation problem for the maximisation of the minimum signal-to-interference-plus-noise ratio across given users. This computationally-intractable non-convex problem is exploited for hidden convexity after which a path-following algorithm with low computational complexity is developed which converges to a local optimal point after a few iterations. Extensive simulation results show that the proposed algorithm of joint design outperforms the alternating optimisations of source power and relay beamforming.